Method for producing fluid mediums of high density



Patented Nov. 17, 1925.

THOMAS H. CHANCE, OF PHILADELPHIA, PENNSYLVANIA.

METHOD FOR PRODUCING FLUID HDI'UIB HIGH DENSITY.

No Drawing.

To all whom it may concern-i Be it known that I, THOMAS M. CnANen, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Methods for Producing Fluid Mediums of High Density, whereof the following is a s ecification.

My invention relates to t e production and maintenance of fluid se arating mediums such as I have described as fluid masses in U. S. Patent No. 1,224,138, issued May 1, 1917, for method and apparatus for separatingv materials of different specific gravities by means of a fluid mass of intermediate specific gravity, said fluid mass consisting of an agitated mixture of li uid and appreciably coarse comminuted soli matter heavier than said liquid and substantially insoluble therein.

In carrying out such se arations, as for example, the separation o coal from slate and other heavy impurities in which the fluid mass used may consist of an agitated mixture of sandand water and in which agitation is efl'ected in part or in whole by water admitted under pressure below the body of said separating fluid mass, the fluidity of said fluid mass and its agitation 80 is effected in whole or in part by said water, which rising upwardly keeps the grains of sand sufliciently separated to insure the maintenance of the desired specific gravity and proper fluidity of the mixture, so that $5 the upwardly rising water, if constant in quantity, maintains an approximately fixed relation between the volume of sand, its voids and the water filling said voids.

The specific gravity of any fluid mass of 40 this type, Whether the liquidused be water or other liquid, and the comminuted solid be sand, natural or artificial, composed of grains of quartz or any other mineral or substance, depends upon the ratio of solids to liquid, the percentage of liquid being equal to the voids between the grains of sand or other material used, the specific gravity increasing as said voids decrease. The specific gravity can therefore be calculated for any relation of sand to voids, thus rises t Application filed December as, 1924. Serial in. 758,783.

40 per cent, sand, sp. gr. 2.65 1. 0600 per cent water, sp. gr. 1.00 6000 6 specific gravity of fluid mass e,. 1. 6600 As the specific gravity is increased by diminishing the percentage of water a limit is reached by reason of the close approach of the grains of sand, the fluid mass becoming thick or viscid and losin the fluidic properties essential to rapid si ing of the eavier of the materials to be se arated.

In the separation of materia s by fluid masses composed of any certain comminuted solid, it often may be advantageous to increase the specific gravity of the fluid mass without decreasing its fluidic properties, or to maintainits specific gravity and increase its fluidity.

I accomplish this end by roviding a fluid mass consisting of a liquid and grains of the comminuted solid used, and referably with a liberal percenta e of voi s, and by providing a secondary fluid mass consisting of a mixture of said liquid and materially smaller grains of comminuted solid matter, said secondary fluid mass having a suflicient percentage of liquid to insure the desired fluidity. This secondary fluid mass is formed, or its constituents are introduced under pressure, below the upper portion of the separating fluid mass and continuously 85 rough the "oids. between the relative coarser ains of the separating fluid mass, thus maintaining the agitation and fluidity of the se arating fluid mass and increasing its speci c gravity by the weight of the vsmaller grains of comminuted solid matter carried by the secondary fluid mass.

The comminuted solid used for the production of the secondary fluid mass may consist of relatively small rains of the same solid used for the pro notion of the separating fluid mass or may consist of grains of any other suitable substantce.

If in the above example, the secondary fluid mass consists of relatively fine grains specific gravity of secondary fluid of quartz, specific gravity 2.05 and is composed of 20 percent fine sand, sp. gr. 2.65"--- .5300 percent water, sp. gr. 1.00 .8000

mass 1.3300

If this fluid mass be used as the liquid for agitating a fluid mass as in the first above example, the specific gravity resulting will be;

40 percent sand, sp. gr. 2.65 1.0600 60 percent secondary fluid mass, sp.

specific gravity of separating fluid mass 1.8580

10 percent magnetite, sp. gr. 5.00-"; percent water, sp. gr. 1.00

specific gravity of secondary fluid mass 1.4000

and if this be used as the liquid for agitating a quartz sand fluid mass as in the above example, the specific gravity will be;

40 percent sand, sp. gr. 2.65 1.0600 60 percent of secondary fluid mass sp. gr. 1.40

specific gravity of separating fluid mass 1.9000

In carrying out my invention the grains of solid matter of the secondary fluid mass should be of such size, weight or shape as to have a materially slower falling velocity in the liquid used than the grains of solid matter provided for the formation of the primary separating fluid mass, in order that they may be carried up through the separating fluid mass and assist in the agitation thereof. The upward velocity of the secondary fluid mass. as a whole, should be sufiicient to maintain it at the required specific gravity, and also to insure the maintenance of the desired percentage of voids in the separating fluid mass. The upward velocity of the liquid of the secondary fluid mass must be materially greater than the falling velocity of the grains of solid matter of said secondary fluid mass in said liquid.

From the foregoing description it will be apparent that the secondary fluid mass rising through the separating fluid mass will accumulate and form a body of fluid mass superposed upon the separating fluid mass unless provision be made for its removal. In carrying out my invention I therefore continuously remove said secondary fluid mass from the upper part of the apparatus in which separation is effected and reintroduce the constituents thereof below the said separating fluid mass, the secondary fluid mass therefore being operated as a practically continuous or closed circuit, provision being made for reconditioning and supplying components lost in the operation of the process.

In carrying out my invention it may often be possible to use a natural or artificial sand the grains of which vary widely in size. When a fluid mass is formed with such materials and agitation is effected mainly or wholly by upwardly rising liquid, the sand grains will soon become sorted by the classifying action of the upwardly rising liquid, the smaller and lighter grains accumulating at the top and forming a fluid mass of generally lower specific gravity superposed upon a fluid mass of coarser grains and usually of higher specific gravity. Under such conditions my invention may be carried out by removing this superposed lighter fluid mass and introducin it or its solid constituent under pressure below the upper part of the said portion of the fluid mass that is of the higher specific gravity, thus increasing the specific gravity of that portion of the fluid mass that is to be used as a fluid medium of relatively. hi h density for the separation of materials 0 different specific gravities by the flotation of the lighter and the sinking of the heavier of said materials.

From the foregoing it will be apparent that the increase in specific gravity obtained by the described method is due to a reduction of the voids by the addition of particles small enough to occupy the voids without actual contact between the larger and smaller particles. The total solids may thus be increased by proper grading of the sizes of the individual particles of solid matter, in a manner quite similar in principle to the grading of sand, gravel, crushed stone, etc. in the preparation of mixes for making concrete with a maximum percentage of coarse and fine aggregate and a. minimum percentage of cement.

The application of my invention to the production of fluid separating mediums by the use of solids other than sand and of liquids other than water will readily be undeistood by those familiar withthe art.

Having described my invention, I claim,

1. A method for producing and maintaining fluid mediums of relatively high density, which consists in agitating a mixture of liquid and comminuted solid matter heavier than said liquid and substantially-insoluble therein by a supply of said liquid introduced under pressure in the region at the lower part of said mixture, whereby a fluid medium of relatively high density is produced and maintained and whereby the smaller and lighter particles of said comminuted solid are continuously carried up through said fluid medium to form an upper division of said agitated mixture, in removing said smaller and lighter particles from said upper division and in introducin said smaller and lighter particles into sai fluid medium at a region materially lower than the top of said fluid medium.

2. A method for producin fluid mediums of relatively high density, w llCh consists in mixing a liquid with comminuted solid matter the individual articles of which are divisible into a plur ity of groups of particles of different sizes, the quantity of particles forming any group being sufiicient to materially reduce the voids in the next coarser group of particles, said comminuted solid matter being heavier than said liquid and substantially insoluble therein, in agitating said mixture to roduce and maintain the fluidity of said mlxture and in transporting the smaller of said particles accumulating m the upper portion of said fluid medium to a region in said fluid medium materially lower than the top of said upper portion.

3. A method for producing and maintaining fluid mediums of relatively high density, which consists in agitating a mixture of liquid and comminuted solid matter heavier than said liquid and substantially insoluble therein by, a supply of said liquid introduced under pressure in the region at the lower part of'said mixture, said colmninuted solid matter being so graded as to the relative sizes of its individual particles as to reduce the interstices between said particles and thus reduce the ratio of voids to solids in said comminuted solid matter, in removing from the upper part of said agitated mixture the smaller particles of said solid mat ter that accumulate therein and in returning said smaller particles to said agitated mixture at a region materially lower than that from which said smaller particles are removed from said agitated mixture.

Signed at Philadelphia, Pennsylvania, this 29th day of December 1924.

THOMAS M. CHANCE. 

